CVE-2026-6554: the tcpdump group libpcap Infinite Loop
CVSS: 5.5v3.1MediumAwaiting analysis
AliasesALPINE-CVE-2026-6554UBUNTU-CVE-2026-6554DEBIAN-CVE-2026-6554
Published 05-09-2026Last modified 08-09-2026
Vulnerability summary
CVE-2026-6554 is a medium (CVSS 5.5) Infinite Loop vulnerability in the tcpdump group libpcap. EPSS estimates a 0.10% chance of exploitation in the next 30 days, higher than 1% of scored vulnerabilities.
CVSS score
5.5/10
010
Medium · v3.1 (CVE.org)EPSS score
0.10%
0%100%
Low · +0.01 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 11 · Related 10Timeline
- 05-09-2026PublishedVulnerability first disclosed.
- 08-09-2026Last modifiedVulnerability information updated.
Description
libpcap BPF interpreter treats the offset in the 'ja L' BPF instruction as a signed integer to implement looping via backward jumps, but it does not limit the number of loop iterations. In particular uncommon use cases a crafted filter program can cause the interpreter to loop infinitely.
CVSS metrics
5 scores · 5 sources · 1 versionMedium 5.5Preferred score · CVE.org (CNA)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HSourcesAll 5 agree
- OSV · AlpineEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- NVDNIST5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.10%
Chance of exploitation in the next 30 days
Percentile
1%
Versus all other CVEs
30-day change
+0.01 pp
From 0.10% on 19-09-2026
19-09-202619-10-2026
EPSS score0.10%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Alpine1 product
- libpcap< 1.10.7-r0
Debian1 product
- libpcapAll versions (No fix recorded) | < 1.10.7-1
The tcpdump group1 product
- libpcap< 1.10.7
Ubuntu1 product
- libpcapAll versions (No fix recorded)
4 vendors · 4 products
